I tried to google N-BALF2 but found nothing. And here is C8 EHD prescription in book. The mirrors system is f/8.5 if you remove corrector. I wonder why using corrector to increase focal length.
I don't think they had complete prescription. Why tweak otherwise? Their lenses are noticeably different (thickness, radii) than what Celestron gives in its file. The closest I can come to it - with all the dimensions nearly identical as in Celestron's drawing - is if I go with 0.707 neutral zone radius (not 0.866 as in the book). No lateral color to speak of, and pretty close blur-size-wise.
With 0.866 zone there has to be more lateral color, or a slight longitudinal chromatism (and that with the corrector pulled a half inch, or so, out). Another possibility is that they go with 0.866 zone and somewhat more relaxed Schmidt radius, giving them ~0.87 zone and minimized lateral color. The secondary is also different than in the standard SCT, so they are not a perfect match for the standard SCT attachments for prime focus imaging anyway.